The present invention relates to an image-pickup apparatus, and more particularly, to an image-pickup apparatus which displays a focus state.
An electronic camera which records static images or moving images has an electronic display apparatus for presenting a preview image used in setting of composition, displaying a picked-up image, or assisting in setting of various image-pickup conditions. The electronic display apparatus includes an electronic viewfinder and a liquid crystal monitor. The electronic viewfinder is a device which is realized by placing a small image display element at a position where a typical optical viewfinder would be provided and allows a user to see an image through an eyepiece. The liquid crystal monitor is a flat-panel image display apparatus which has a relatively large screen, is placed at the exterior of a camera such as on the back and the side, and allows a user to see an image directly.
The electronic display apparatus is also used to check a focus state in the imaging time. The electronic display apparatus, however, typically has a low resolution, so that it is difficult for a user to accurately know the focus state if a preview image is presented as it is. To address this, various techniques have been proposed for improving the visibility of the focus state of the preview image (see, for example, Japanese Patent Laid-Open No. 2004-212891, Japanese Patent Laid-Open No. 11 (1999)-122517, Japanese Patent Laid-Open No. 2005-181373).
Other related arts include Japanese Patent Laid-Open No. 61(1986)-22316, Japanese Patent Laid-Open No. 9(1997)-184972, Japanese Patent Laid-Open No. 6(1994)-175015, Japanese Patent Laid-Open No. 2003-140246, and Japanese Patent Laid-Open No. 2000-2909.
In Japanese Patent Laid-Open No. 2004-212891, an image in a focus detection area is divided into two and the two images are shifted horizontally and displayed. It is difficult to accurately recognize such a horizontal shift for an image having a complicated shape. In Japanese Patent Laid-Open No. 11 (1999)-122517, two images are horizontally shifted in accordance with the difference between the two images by using triangulation. Since image-pickup systems for picking up the two images have different characteristics, the display quality is low when focus is achieved, and it is difficult to accurately recognize a small out-of-focus amount. Japanese Patent Laid-Open No. 2005-181373 includes an electronic viewfinder which presents a difference in focus evaluation value and the polarity thereof in two images before and after manual focusing operation. This prevents a user from seeing an object in a focus detection area and its focus state simultaneously. Thus, the user cannot know the focus state continuously while keeping track of a quickly moving object in the focus detection area.